Yamaha MM700A Manual page 50

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check the coil to verify that the unit is faulty before buying
a replacement.
NOTE
Normal resistance in both the primary and
secondary (high-tension) coil windings is
not aguarantee the unit is workingproperly.
Only an operational spark test can indicate
whether a coil is producing an adequate
spark from the input voltage. A Yamaha
dealership may have the equipment to test
the coil's output. I f not, substitute a known
good coil and check engine operation.
Ignition pickup coil
The ignition pickup coil is located just outside the fly-
wheel.
1. Open the shroud.
2. Disconnect the rectangular six-wire connector located
near the CDI box.
3. Connect an ohmmeter between the white/green and
(Figure 9).
4. Compare the reading to the specification in Table 1. If
the reading is not within specifications, replace the pickup
coil and stator assembly as described in Chapter Six.
5. Reattach the connector.
6. Close the shroud.
Ignition source coil
The ignition source coil is located in the stator.
1. Open the shroud.
2. Disconnect the rectangular six-wire connector and
three-wire triangular connector located near the CDI box.
3. Connect an ohmmeter between the black/red and
brown wire terminals in the triangular connector from the
ignition pickup coil (Figure 10).
4. Compare the reading to the specification in Table 1. If
the reading is not within specifications, replace the stator
assembly as described in Chapter Six.
5. Connect an ohmmeter between the brown/red wire ter-
minal in the triangular connector and the black wire termi-
nal in the rectangular connector from the ignition pickup
coil (Figure 10).
6. Compare the reading to the specification in Table 1. If
the reading is not within specifications, replace the stator
assembly as described in Chapter Six.
7. Reattach the connectors.
8. Close the shroud.
BATTERY CHARGING SYSTEM
(MODELS WITH ELECTRIC START)
The charging system consists of a charge coil contained
in the stator assembly, permanent magnets located within
the flywheel rim, a rectifier to change alternating current
(AC) to direct current (DC), the battery and connecting
wiring. The rectifier is a solid state device that also con-
tains a regulator to prevent overcharging of the battery.
See Figure
11.
A malfunction in the charging system generally causes
charge coil is protected by its location underneath the fly-
wheel, it is more likely the battery, rectifier/regulator or
connecting wiring will cause problems.
Troubleshooting Preparation
Before testing the charging system, visually check the
following:
1. Check the fuse. Replace the fuse if blown.
2. Make sure the battery cables are properly connected. If
polarity is reversed, check for a damaged rectifier.
3. Check battery condition. Clean and recharge as re-
quired. See Chapter Six.
4. Carefully inspect all wiring between the magneto base
and battery for worn or cracked insulation and corroded or
loose connections. Replace wiring or clean and tighten
connections as required.
CHAPTER TWO